Welcome to the Pyongyang Metro. A ticket to travel will set you back a paltry 5 won, which, at the time of writing, is $0.006 (£0.004).

Here is where the MTR will take you. It is currently formed of two lines — the Chollima Line and the Hyŏksin Line. Stations are not named after places, but revolutionary phraseology, such as Kaeson, meaning 'Triumph.'

The Pyongyang Metro is 110 metres underground, making it one of the deepest subway systems in the world. It's so deep that stations double up as bomb shelters — hallways are protected by thick steel blast doors.

The interiors of the subway stations are often opulent, boasting marble pillars, chandeliers, and paintings of Kim Jong-il.

The trains themselves are ex-German cars, purchased in the late 1990s. It's hard to tell the carriages' past as they have been carefully painted over, though, some German graffiti in the carriage interiors lets the secret slip.